Tau cleavage and tau aggregation in neurodegenerative disease

2010 ◽  
Vol 38 (4) ◽  
pp. 1016-1020 ◽  
Author(s):  
Diane P. Hanger ◽  
Selina Wray
Keyword(s):  
Neurodegenerative Disease ◽  
Conformational Changes ◽  
Tau Phosphorylation ◽  
Cell Models ◽  
Tau Pathology ◽  
Binding Domains ◽  
Pathological Conditions ◽  
Tau Aggregation ◽  
The Brain ◽  
Tau Cleavage

Deposition of highly phosphorylated tau in the brain is the most significant neuropathological and biochemical characteristic of the group of neurodegenerative disorders termed the tauopathies. The discovery of tau fragments in these diseases suggests that tau cleavage and tau phosphorylation, both of which induce conformational changes in tau, could each have roles in disease pathogenesis. The identities of the proteases responsible for degrading tau, resulting in the appearance of truncated tau species in physiological and pathological conditions, are not known. Several fragments of tau are reported to have pro-aggregation properties, but the lack of disease-relevant cell models of tau aggregation has hampered investigation of the effects of tau aggregation on normal cellular functioning. In the present paper, we describe our findings of N-terminally truncated tau in the brain in a subgroup of the tauopathies in which tau isoforms containing four microtubule-binding domains predominate. We also discuss the evidence for the involvement of proteases in the generation of tau pathology in neurodegenerative disease, since these enzymes warrant further investigation as potential therapeutic targets in the tauopathies.

scholarly journals Antisense Oligonucleotide-Mediated Reduction of HDAC6 Does Not Reduce Tau Pathology in P301S Tau Transgenic Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Antonio Valencia ◽  
Veronica L. Reinhart Bieber ◽  
Bekim Bajrami ◽  
Galina Marsh ◽  
Stefan Hamann ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Tau Protein ◽  
Antisense Oligonucleotide ◽  
Tau Phosphorylation ◽  
Histone Deacetylase 6 ◽  
Tau Pathology ◽  
Tau Aggregation ◽  
The Brain ◽  
Mediated Reduction ◽  
Tau Acetylation

Acetylation of tau protein is dysregulated in Alzheimer's Disease (AD). It has been proposed that acetylation of specific sites in the KXGS motif of tau can regulate phosphorylation of nearby residues and reduce the propensity of tau to aggregate. Histone deacetylase 6 (HDAC6) is a cytoplasmic enzyme involved in deacetylation of multiple targets, including tau, and it has been suggested that inhibition of HDAC6 would increase tau acetylation at the KXGS motifs and thus may present a viable therapeutic approach to treat AD. To directly test the contribution of HDAC6 to tau pathology, we intracerebroventricularly injected an antisense oligonucleotide (ASO) directed against HDAC6 mRNA into brains of P301S tau mice (PS19 model), which resulted in a 70% knockdown of HDAC6 protein in the brain. Despite a robust decrease in levels of HDAC6, no increase in tau acetylation was observed. Additionally, no change of tau phosphorylation or tau aggregation was detected upon the knockdown of HDAC6. We conclude that HDAC6 does not impact tau pathology in PS19 mice.

P2-044: Inducible cell models of tauopathy show that tau aggregation is toxic to cells, but tau pathology can be reversed

2006 ◽  
Vol 2 ◽  
pp. S245-S245
Author(s):  
Jacek Biernat ◽  
Inna Khlistunova ◽  
Yipeng Wang ◽  
Marcus Pickhardt ◽  
Zuzana Gazova ◽  
...  
Keyword(s):  
Cell Models ◽  
Tau Pathology ◽  
Tau Aggregation

scholarly journals Impairments in Brain Bioenergetics in Aging and Tau Pathology: A Chicken and Egg Situation?

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2531
Author(s):  
Amandine Grimm
Keyword(s):  
Brain Metabolism ◽  
Brain Aging ◽  
Cognitive Impairments ◽  
Tau Phosphorylation ◽  
The Body ◽  
Tau Pathology ◽  
Age Related ◽  
Energy Consuming ◽  
Effects Of Aging ◽  
The Brain

The brain is the most energy-consuming organ of the body and impairments in brain energy metabolism will affect neuronal functionality and viability. Brain aging is marked by defects in energetic metabolism. Abnormal tau protein is a hallmark of tauopathies, including Alzheimer’s disease (AD). Pathological tau was shown to induce bioenergetic impairments by affecting mitochondrial function. Although it is now clear that mutations in the tau-coding gene lead to tau pathology, the causes of abnormal tau phosphorylation and aggregation in non-familial tauopathies, such as sporadic AD, remain elusive. Strikingly, both tau pathology and brain hypometabolism correlate with cognitive impairments in AD. The aim of this review is to discuss the link between age-related decrease in brain metabolism and tau pathology. In particular, the following points will be discussed: (i) the common bioenergetic features observed during brain aging and tauopathies; (ii) how age-related bioenergetic defects affect tau pathology; (iii) the influence of lifestyle factors known to modulate brain bioenergetics on tau pathology. The findings compiled here suggest that age-related bioenergetic defects may trigger abnormal tau phosphorylation/aggregation and cognitive impairments after passing a pathological threshold. Understanding the effects of aging on brain metabolism may therefore help to identify disease-modifying strategies against tau-induced neurodegeneration.

scholarly journals Similarities and Differences in the Pattern of Tau Hyperphosphorylation in Physiological and Pathological Conditions: Impacts on the Elaboration of Therapies to Prevent Tau Pathology

2021 ◽  
Vol 11 ◽  
Author(s):  
Antoine Duquette ◽  
Camille Pernègre ◽  
Ariane Veilleux Carpentier ◽  
Nicole Leclerc
Keyword(s):  
Protein A ◽  
Hyperphosphorylated Tau ◽  
Tau Hyperphosphorylation ◽  
Therapeutic Approaches ◽  
Tau Pathology ◽  
Physiological Conditions ◽  
The Third ◽  
Pathological Conditions ◽  
The Brain

Tau protein, a neuronal microtubule-associated protein, becomes hyperphosphorylated in several neurodegenerative diseases called tauopathies. Hyperphosphorylation of tau is correlated to its redistribution from the axon to the somato-dendritic compartment at early stages of tauopathies. Interestingly, tau hyperphosphorylation begins in different regions of the brain in each tauopathy. In some regions, both neurons and glial cells develop tau hyperphosphorylation. Tau hyperphosphorylation is also observed in physiological conditions such as hibernation and brain development. In the first section of present article, we will review the spatiotemporal and cellular distribution of hyperphosphorylated tau in the most frequent tauopathies. In the second section, we will compare the pattern of tau hyperphosphorylation in physiological and pathological conditions and discuss the sites that could play a pivotal role in the conversion of non-toxic to toxic forms of hyperphosphorylated tau. Furthermore, we will discuss the role of hyperphosphorylated tau in physiological and pathological conditions and the fact that tau hyperphosphorylation is reversible in physiological conditions but not in a pathological ones. In the third section, we will speculate how the differences and similarities between hyperphosphorylated tau in physiological and pathological conditions could impact the elaboration of therapies to prevent tau pathology. In the fourth section, the different therapeutic approaches using tau as a direct or indirect therapeutic target will be presented.

scholarly journals Tau in the brain interstitial fluid is fragmented and seeding-competent

2020 ◽  
Author(s):  
Erica Barini ◽  
Gudrun Plotzky ◽  
Yulia Mordashova ◽  
Jonas Hoppe ◽  
Esther Rodriguez-Correa ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Interstitial Fluid ◽  
List Type ◽  
Fragmentation Pattern ◽  
Tau Pathology ◽  
Brain Areas ◽  
Brain Interstitial Fluid ◽  
Tau Aggregation ◽  
The Brain

SUMMARYIn Alzheimer disease, Tau pathology is thought to propagate from cell to cell throughout interconnected brain areas. However, the forms of Tau released into the brain interstitial fluid (ISF) in vivo during the development of Tauopathy and their pathological relevance remain unclear. Combining in vivo microdialysis and biochemical analysis, we find that human Tau (hTau) present in brain ISF is truncated and comprises at least 10 distinct fragments spanning the entire Tau protein. The fragmentation pattern is similar across different Tau transgenic models, pathological stages and brain areas. ISF hTau concentration decreases during Tauopathy progression, while its phosphorylation increases. ISF from mice with established Tauopathy induces Tau aggregation in HEK293-Tau biosensor cells and notably, only a small fraction of Tau, separated by ultracentrifugation, is seeding competent. These results indicate that only a subset of Tau accounts for ISF seeding competence and have the potential to contribute to the propagation of Tau pathology.Graphical abstractHighlights✓In transgenic mice, interstitial fluid comprises several Tau fragments spanning the entire Tau sequence.✓Interstitial fluid Tau concentration decreases with Tauopathy progression, while phosphorylation increases.✓Only interstitial fluid from mice with established Tauopathy is seeding competent in vitro.✓Interstitial fluid seeding competence is driven by less soluble, aggregated and phosphorylated Tau species.In BriefBarini et al. show that in the brain interstitial fluid of Tau transgenic mice, truncated Tau decreases, while its phosphorylation increases during the progression of pathology. A subset of less soluble, aggregated and phosphorylated ISF Tau induces Tau aggregation in cells.

scholarly journals The Norepinephrine Metabolite DOPEGAL Confers Locus Coeruleus Tau Vulnerability and Propagation via Asparagine Endopeptidase

2019 ◽  
Author(s):  
Seong Su Kang ◽  
Xia Liu ◽  
Eun Hee Ahn ◽  
Jie Xiang ◽  
Fredric P. Manfredsson ◽  
...  
Keyword(s):  
Monoamine Oxidase ◽  
Locus Coeruleus ◽  
Selective Vulnerability ◽  
Monoamine Oxidase A ◽  
Noradrenergic Neurons ◽  
Tau Pathology ◽  
Intact Cells ◽  
Tau Aggregation ◽  
The Brain

AbstractAberrant Tau inclusions in the locus coeruleus (LC) are the earliest detectable Alzheimer’s disease (AD)-like neuropathology in the human brain; however, why LC neurons are selectively vulnerable to developing early Tau pathology and degenerating later in disease and whether the LC might seed the stereotypical spread of Tau pathology to the rest of the brain remain unclear. Here we show that 3,4-dihydroxyphenylglycolaldehyde (DOPEGAL), which is produced exclusively in noradrenergic neurons by monoamine oxidase A (MAO-A) metabolism of norepinephrine (NE), activates asparagine endopeptidase (AEP) that cleaves Tau at residue N368 into aggregation- and propagation-prone forms, thereby leading to LC degeneration and the spread of Tau pathology. DOPEGAL triggers AEP-cleaved Tau aggregationin vitroand in intact cells, resulting in LC neurotoxicity and propagation of pathology to the forebrain. Thus, our findings reveal a novel molecular mechanism underlying the selective vulnerability of LC neurons in AD.

scholarly journals Delta-secretase cleavage of Tau mediates its pathology and propagation in Alzheimer’s disease

2020 ◽  
Vol 52 (8) ◽  
pp. 1275-1287
Author(s):  
Seong Su Kang ◽  
Eun Hee Ahn ◽  
Keqiang Ye
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Therapeutic Strategy ◽  
Senile Plaques ◽  
Tau Pathology ◽  
Disease Modifying ◽  
Tau Aggregation ◽  
The Brain ◽  
Insight Into

Abstract Alzheimer’s disease (AD) is a progressive neurodegenerative disease with age as a major risk factor. AD is the most common dementia with abnormal structures, including extracellular senile plaques and intraneuronal neurofibrillary tangles, as key neuropathologic hallmarks. The early feature of AD pathology is degeneration of the locus coeruleus (LC), which is the main source of norepinephrine (NE) supplying various cortical and subcortical areas that are affected in AD. The spread of Tau deposits is first initiated in the LC and is transported in a stepwise manner from the entorhinal cortex to the hippocampus and then to associative regions of the neocortex as the disease progresses. Most recently, we reported that the NE metabolite DOPEGAL activates delta-secretase (AEP, asparagine endopeptidase) and triggers pathological Tau aggregation in the LC, providing molecular insight into why LC neurons are selectively vulnerable to developing early Tau pathology and degenerating later in the disease and how δ-secretase mediates the spread of Tau pathology to the rest of the brain. This review summarizes our current understanding of the crucial role of δ-secretase in driving and spreading AD pathologies by cleaving multiple critical players, including APP and Tau, supporting that blockade of δ-secretase may provide an innovative disease-modifying therapeutic strategy for treating AD.

scholarly journals Role of the Lipid Membrane and Membrane Proteins in Tau Pathology

2021 ◽  
Vol 9 ◽  
Author(s):  
Eugene Bok ◽  
Eunju Leem ◽  
Bo-Ram Lee ◽  
Ji Min Lee ◽  
Chang Jae Yoo ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Lipid Membrane ◽  
Cell Types ◽  
Tau Pathology ◽  
Membrane Interaction ◽  
Extracellular Milieu ◽  
Abnormal Accumulation ◽  
Tau Aggregation ◽  
The Brain

Abnormal accumulation of misfolded tau aggregates is a pathological hallmark of various tauopathies including Alzheimer’s disease (AD). Although tau is a cytosolic microtubule-associated protein enriched in neurons, it is also found in extracellular milieu, such as interstitial fluid, cerebrospinal fluid, and blood. Accumulating evidence showed that pathological tau spreads along anatomically connected areas in the brain through intercellular transmission and templated misfolding, thereby inducing neurodegeneration and cognitive dysfunction. In line with this, the spatiotemporal spreading of tau pathology is closely correlated with cognitive decline in AD patients. Although the secretion and uptake of tau involve multiple different pathways depending on tau species and cell types, a growing body of evidence suggested that tau is largely secreted in a vesicle-free forms. In this regard, the interaction of vesicle-free tau with membrane is gaining growing attention due to its importance for both of tau secretion and uptake as well as aggregation. Here, we review the recent literature on the mechanisms of the tau-membrane interaction and highlights the roles of lipids and proteins at the membrane in the tau-membrane interaction as well as tau aggregation.

scholarly journals Efficient propagation of misfolded tau between individual neurons occurs in absence of degeneration

2018 ◽  
Author(s):  
Grace I Hallinan ◽  
Mariana Vargas-Caballero ◽  
Jonathan West ◽  
Katrin Deinhardt
Keyword(s):  
Cell Death ◽  
Axonal Transport ◽  
Tau Protein ◽  
Neuronal Death ◽  
Early Event ◽  
Neuronal Dysfunction ◽  
Tau Pathology ◽  
Functional Consequences ◽  
Tau Aggregation ◽  
The Brain

AbstractIn Alzheimer’s disease, misfolded tau protein propagates through the brain in a prion-like manner along connected circuits. Tauopathy correlates with significant neuronal death, but the links between tau aggregation, propagation, neuronal dysfunction and death remain poorly understood, and the direct functional consequences for the neuron containing the tau aggregates are unclear. Here, by monitoring individual neurons within a minimal circuit, we demonstrate that misfolded tau efficiently spreads from presynaptic to postsynaptic neurons. Within postsynaptic cells, tau aggregates initially in distal axons, while proximal axons remain free of tau pathology. In the presence of tau aggregates neurons display axonal transport deficits, but remain viable and electrically competent. This shows that misfolded tau species are not immediately toxic to neurons, and suggests that propagation of misfolded tau is an early event in disease, occurring prior to neuronal dysfunction and cell death.

scholarly journals Connectome-mediated prediction of future tau-PET burden in Alzheimer’s disease

2020 ◽  
Author(s):  
Pablo F. Damasceno ◽  
Renaud La Joie ◽  
Sergey Shcherbinin ◽  
Sudeepti Southekal ◽  
Vikas Kotari ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Drug Efficacy ◽  
Current Evidence ◽  
Cognitively Impaired ◽  
Tau Pathology ◽  
Disease Modifying Therapies ◽  
Tau Aggregation ◽  
The Brain ◽  
Combined Data

Alzheimer’s Disease (AD) tau pathology originates in the brainstem and subsequently spreads to the entorhinal cortex, hippocampus and finally to temporal, parietal and prefrontal association cortices in a relatively stereotyped progression. Current evidence attributes this orderly progression to trans-neuronal spread of misfolded tau protein along the projection pathways of affected neurons. The aggregation of tau is being increasingly recognized as a trustworthy biomarker preceding the appearance of Alzheimer’s disease (AD) symptoms. One major goals of disease modifying therapies has been to stop or slow down the tau aggregation process. In order to evaluate drug efficacy, it would be desirable to have an accurate model predictive of a patient’s future tau burden, against which the tau measurements from drug-receiving cohorts could be compared. Here we report the development of such a model, evaluated in a cohort of 88 subjects clinically diagnosed as Mild Cognitively Impaired (MCI = 60) or Alzheimer’s disease (AD = 28) and tracked over a period of 18 months. Our approach combined data-driven and model-based methodologies, with the goal of predicting changes in tau within suitably specified target regions. We show that traditional statistical methods, allied to a network diffusion model for tau propagation in the brain, provide a remarkable prediction of the magnitude of incremental tau deposited in particular cortical areas of the brain over this period (MCI: R2 = 0.65±0.16; AD: R2 = 0.71±0.11) from baseline data. Our work has the potential to greatly strengthen the repertoire of analysis tools used in AD clinical trials, opening the door to future interventional trials with far fewer sample sizes than currently required.

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